There are components for driving in a vehicle engine room, such as an engine and various heat exchangers, such as an intercooler, evaporator, and condenser.
Heat exchange media mainly flow inside of the heat exchangers described above, and the heat exchange media in the heat exchangers and air outside of the heat exchangers mutually exchange heat whereby cooling or radiation is performed, and for a stable operation of the various heat exchangers in the vehicle engine room the external air must be satisfactorily provided into the engine room.
However, when a vehicle drives in a high speed, a large amount of external air quickly flow in whereby an air resistance becomes extremely large, thereby increasing fuel consumption.
To solve that problem, an active air flap is developed which increasing an opening angle in a low speed thereby increasing the inflow amount of the air, and decreasing the opening angle in the high speed, thereby decreasing the inflow amount of the air and improving the fuel consumption.
There are a built-in air flap (shroud duct type) which controls an opening and closing of a flap by a flap driver installed behind a duct surrounding a radiator grill, and an external air flap (radiator-grill integrated type) which controls to directly open and close by making the radiator grill act as the flap disclosed in the conventional art.
The built-in active air flap described above has higher design freedom and is subject to less package constraint of the flap driver compared to the external active air flap which has an effect of improving an aerodynamic performance compared to the built-in active air flap.
However, the external active air flap is constructed in such a way that the radiator grill acts as flap which controls the inflow of the exterior air, and thereby, a large torque is required to forcedly open and close the flap in a high speed condition, and a motor of larger capacity must be used for the larger torque, thus increasing cost.
The description provided above as a related art of the present disclosure is just for helping in understanding the background of the present disclosure and should not be construed as being included in the related art known by those skilled in the art.